Method of locating and repairing suction strainer damages in wells



ay 14, 1940. R N 2,201,096

METHOD OF LOCATING AND REPAIRING SUCTION STRAINER DAMAGES IN WELLS Filed July 5, 1938 2 Sheets-Sheet 1 Fi .1. Fig.2.

E. KERMAN May 14, 1940.

Filed July 5, less 2 Sheets-Sheet 2 Patented May l4, 1940 PATENT OFFICE METHOD OF LOCATING AND REPAIRING SUCTION STRAINER DAMAGESIN WELLS Ernest Kerman, Kfar-Saba, Palestine Application July5, 1938, Serial No. 217,441 ln lalestine July 7, 1937 1 the suction pipe and if the pumped water is free ofsand, the inflatable flexible tube covers the place of damage. If the pumped wateris not free of sand, the place of damage is not covered and the inflatable flexible tube must be shifted until the place of damage is found.

After the damage is located the endless tube or tubes made of rubber, leather, impermeable canvas or other materials may be inflated by substances such as paraflin, plaster of Paris or cemeht mixed with water or bees-wax or the like, in a liquid form which subsequently solidify in order to effect a permanent repair.

The suction strainers generally used consist of an ironpipe provided with a. large number of holes. The pipe is covered on its exterior by 'a dense netting ofcopper wire (galvanized). This netting is wrapped in sheet form around the pipe and soldered to it. Damages may sometimes be caused by mechanical injury by sharp or pointed objects which fall into the strainer in the well. In their fall these objects strike the inside walls of the strainer, piercing the netting of copper wire covering the holes of the strainer. Thus damages are caused to the strainer preventing it from fulfilling its functions and allowing sand to be drawn through the strainer. The well is thus gradually undermined since the sand is drawn through the strainer from the bottom and the sides of thewell, and may in time collapse causing all sorts of accidents. The installation of a new strainer in place of the injured one means additional expense and a considerable loss of time.

In my method inflatableflexible tubes are introduced into suction strainers from above, en-

circling the suction pipe'by means of rods, wires, ropes and the like. They are inflated and defiated in the suction strainer in such a manner that different parts of the suction strainer are alternately usedfor straining water fromthe sand, thereby enabling the worker to ascertain the depth at which the strainer is damaged. ,Subsequ'ntly a tube is inflated over the damaged portion' of the strainer, or two tubes encircling a suction pipe, any pipe or otherobjects are inflated above and below the damaged portion. Thus, a. minimum of the portion of the strainer is isolated (therefore not utilized for. straining water) and the damage is covered and permanently repaired.

My method applied in three diflerent ways will be further explained with reference to the accompanying drawings. in which Figs. 1, 2 and 3 are vertical cross-sections of suction pipe and strainer.

In Fig. 1 a portion of a strainer I is shown. The suction pipe 2 is shown with an inflatable flexible endless tube 3, encircling the bottom end thereof. In order to do this suction pipe 2 is removed from the strainer l, tube 3 being drawn 15 tightly onto the suction pipe 2. It is thenreplaced into the strainer I. The tube 3 encircling the suction pipe 2 is connected to a compressor or a pump by means of a tube 4 which is provided with a manometer 5. If liquids are used to in- 20 flate the tube it is suflicient to pour a liquid of higher density than water into tube 4 (by means of a funnel.) Examples of such liquids are salt water, nitrates dissolved in water and the like.

It is possible to hold the opening of tube 4 a few 25 meters above the water level in the well, and to pour the liquid into it by means of a funnel. The difference of the water levels inside and outside the tube 4 is suflicient to inflate tube 3. The tube 3' is inflated with air, water or any suitan able gas or liquid and is so enlarged by inflation that it completely and tightly encircles the bot- 'tomend of pipe 2 and is pressed against the walls of the strainer l .as shown in Fig. 1. If the pump is set in motion it pumps only the water coming through that part of the strainer which is below the inflated tube 3. If after a short period of pumping, the water is found to be free of sand, it is understood that the damage must lie above the inflated tube 3. If the pumped water 40 is not free of sand, it indicates that the damage lies below the inflated tube 3. In the latter case, the operation must be repeated lowering the tube 3 deeper into the well, and so on until the damage is located over the inflated tube 3. The suction 45 pipe 2 is disconnected from the pump and lengthened by screwing an additional piece of pipe on its upper extremity. The bottom of the lengthened suction pipe 2 and therefore tube 3 are now deeper in the well. 50

Another application of my method is illustrated ,in Fig. 2. After disconnection and removal of suction pipe 2, two pipes 6 and 1 are introduced into the strainer and supported from above by wires or other means, whereupon the 55 and manometer suction pipe 2 is fitted again in the well. Pipes 6 and 1 have been constructed so that pipe 6 is of a smaller diameter than pipe 1 and easily passes through it. Encircling the ends of pipe I are two inflatable flexible tubes 8 and 8' to which is connected a long and thin tube 4" which leads out of the strainer to a compressor Likewise encircling pipe 6 are two inflatable flexible tubes 9 and 9 to which is connected along and thin tube 4' which leads out of the strainer to a compressor and manometer 5'. Another inflatable bag l0 which is intro-- duced into pipe Gis connected to a long and thin tube 4" which leads out of the strainer to a compressor and manometer 5". Now tubes 9, 9 and bag ID are inflated, shutting off all contact between the water above and below the pipe 6, inflatable tubes of pipe 1 being as yet not inflated. The pump is set in motion and .if the water is not free of sand, it is understood that the strainer is damaged above the pipe 6. Now We inflate tubes 8, 8' of pipe I and if the pumped water is not free of sand, it is understood that the damage is not between the tubes 8 and 8. Then we deflate tubes 8 and 8 of pipe 1 and move the latter up or down, repeating the process until we obtain water free of sand thus indicating that the damage is now located and-is between the tubes 8 and 8'.

Now the bag [0 of pipe 6 is deflated and if ,the pumped water remains clear of sand, it

means that there are no damages under pipe 1. Then the tubes 9 and 9' of pipe 6 are deflated and pipe 6 is withdrawn from the strainer. The pipe I which, as explained above, has been manoeuvred over the damaged portion of the strainer and tubes 8 and 8' inflated, thereby shutting oif the flow of sand into the strainer,

-must remain in the strainer permanently.

Endless tubes 8 and 8' may be inflated by substances such as paraffin, plaster of Paris or cement mixed with water or bees-wax or the like, in a liquid form which subsequently solidify. Thus the damage which is located between tubes 8 and 8 is repaired by the isolation of the damaged place as described.

Fig. 3 shows an alternative method of repairing the damage as described with reference to Fig. 2 after the damage has been located according to the method described in the preceding paragraphs. In Fig. 3 we see pipe I which fulfills the same functions as pipe I in Fig. 2 but here fulfllls other functions as well, as will be subsequently shown.

This pipe 1' is encircled by two pairs of tubes 9" and 9" and II and II. The exterior of pipe 1' between the inner pair of tubes II and H is covered with a film ll of a solid substance such as paraflin, bees-wax, plaster of Paris or any other like substances which may subsequently 'be melted or dissolved. The space between this fllm l2 and the strainer l is filled, by means of a tube introduced from above, with concrete or like substance, the pipe 1' and the film l2 being provided with a hole or holes for this purpose.

After the fllm i2 has beenmelted or dissolved by pouring hot water into strainer I, by electric heating or other means, the inflated tubes are deflated, pipe 6 and all its accessories, are withdrawn the damaged place being covered by a solid film I 3.

In case the solid film I3 is very thin, it may be reinforced by a metal cylindrical sheet l5 which was provided above before the pipe I was introduced into the strainer.

' of thismethod are possible.

essentially based upon the utilization of any pipe, other pipes or other objects, and

4 both ends.

Between the lower pair of tubes 9" and II as well as the upper pair 9" and H, sand or like substance mixed with water may be poured in from above by means of tubes. This is done before the cement is poured into space 13.

The water of the above mixture percolates through the strainer l into the strata surrounding the strainer I causing the sand to pack together tightly. This prevents the cement from running out into the other parts of the strainer.

The above description contains several variations of the method which I have invented. But it must be understood that many more variations The method is number of inflatable flexible endless tubes which are introduced into wells encircling a suction which are then inflated.

-In my method I used a device essentially consisting of a support upon which one or more inflatable flexible tubes are mounted or upon which is drawn any inflatable material.

These tubes or inflatable material are connected to compressors -by means of thin tubes made of rubber or any other substance, and thus inflated or filled with gas or liquids which subsequently solidify.

The support may have the form of a piece of metal pipe, an empty prism with any number of faces, a cylinder, a barrel and the likemade of wood, metal or any convenient material. The

tubes or inflatable material are made of rubber, v

Fig. 5 shows a vertical cross-section of thedevice of Fig. 4.

Fig. 6 shows another device in which inflatable material is drawn upon a cylindrical support.

Fig. 7' shows a vertical cross-section of the device of Fig. 6.

The device of Fig. 4 is composed of an inflatable flexible tube l6 mounted on a piece of pipe I! which is inflated by means of a thin tube It. This inflatable flexible tube l6 when inflated is pressed against the walls of the strainer 9. The deviceof Fig. 6 is composed of a piece of pipe 20 which servesas a support and upon which is drawn rubber or other inflatable material bound by iron hoops or rings 22 to the support 20 on This inflatable material 2| is connected to a thin pipe 23 through the interior of the support 20 in which a hole 24 is made.

Having thus described my invention, what I claim is:

1. A method of repairing damages inside strainers in wells characterized by the use of inflatable casings surrounding hollow bearers, said casings being connected to thin tubes leading above and out of strainers, said casings being shifted inside the strainers until the damaged portions are covered by the casings which are then inflated by means of said tubes with liquids or pastes which subsequently solidify.

, 2. A method of repairing damages inside strainers in wells characterized by the use of inflatable casings surrounding hollow bearers, said casings being connected to thin tubes leading above and out of strainers, said casings being shifted inside the strainers until the damaged portions are isolated between two such casings by inflation; the casings being inflated by means of said tubes with liquids or pastes which subsequently solidify.

3. A method of repairing damages inside strainers in wells characterized by the use oi inflatable casings surrounding hollow bearers, said casings being connected to thin tubes leading above and out of strainers, said casings being shifted inside the casings until the damaged portions are covered by the casings which are then inflated by means of said tubes with liquids or pastes which solidify, but can subsequently be melted or dissolved.

4. A method of repairing damages inside strainers in wells characterized by theuse of inflatable casings surrounding hollow bearers, said casings being connected to thin tubes leading above and out of strainers, said casings being shifted inside the strainers until the damaged portions are isolated between two such casings by inflation, the casings being inflated by means of said tubes with liquids or pastes which solidify but can subsequently be melted or dissolved.

5. A, method of-repairing strainerdamages in wells by isolating damaged portion of strainer between two inflatable packers mounted on a hollow bearer subsequently injecting cementing material by means of tubes piercing the bearer into the space between the two packers, the

strainer and the bearer.

i ERNEST KERMAN. 

